I'm going to drop the motor out of my 75 next week to replace the fan. How high do I need to get the car in the air to have the motor clear out the bottom?

geez, no one has answered by now....

about 2 1/2 feet. 3' with a rolling jack. that'll give yo a bit of room for error.

as high as ya want

check the "engine removal" tech article
top of the page, click "914 info" and then "tech articles"
IIRC, the info is there...

Here is a visual:

'nuther, just for reference:

Thanks Guys for pointing me in the right direction and thanks Mark for the Tech article. I should have known it was on this site somewhere.